US2530257A

US2530257A - Apparatus for testing coatings

Info

Publication number: US2530257A
Application number: US567409A
Authority: US
Inventors: Jerome R Marcus
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1944-12-09
Filing date: 1944-12-09
Publication date: 1950-11-14
Anticipated expiration: 1967-11-14

Description

Nov. 14, 19.50 J. R. MARCUS 2,530,257

APPARATUS FOR TESTING COATINGS Filed Dec. 9, 1944 4 Shasta-Sheet 1 rusa nec. 1944 4 Sheets-Sheet 2 S QN NN QN s .MA/ m .QW NN .\NN um .wn E RM? N 7%////// Mim .Q 1 nw Q k vill Il J. R. MARCUS APPARATUS FOR TESTING COATINGS Nov. 14, 1950 4 Sheets-Shut `4 Filed Dec. 9. 1944 Patented Nov. 14,

UNITED vSTATES 1 PATENT omer:

' 2,530,251 Y. MZ..-

ern Electric Company, N. Y., a corporation of New York Incorporated, New York.

Anuncie neeembees, im, sel-m 116.501,40

(ci. vs -1s.)

schim. l

This invention relates .neat'h the beam. The beam is pivoted ior oscillation and carries a weight supporting carriage which maybe fed along the beam. to change the lever arm thereof. by a motor driven screw driving in synchronism with a driving screw for the carriage which supports the specimen whereby.V

after one of the probes has been selectively rendered operable, the lever arm oi the beam is. -gradually changed to apply a gradually increasing' weight to the probe engaging a test sample on -the carriage and simultaneously therewith the carriage is moved to drag the -test specimen in the path oi the probe. A

control circuit is provided whereby the driving power for the motor is interrupted when a probe breaks through the paint coating on the test specimen, and the position oi the weight at the time that the motor circuit is interrupted may be read upona scale scribed on the beam, thereby to force a probe through the paint coating.

' to apparatus for testing coatings and more particularly to an apparatus 2 in the direction of the arrows showing the specimen supporting carriage in end elevation;

llig.'lisanirregularverticalsectionalviewon an enlarged scale, taken substantially along the linel-l oi Fig. 1 in the direction of the arrows, and showing the specimen supporting carriage and drive therefor in section;

Fig. 8 is a longitudinal sectional view on an enlarged scale. taken substantially along the line l-j oi. Fig. 3 in the direction oi the arrows and showing' the detalls of the drive for the weight supporting carriage and specimen supporting carriage;

Fig. 9 is an enlarged fragmentary side elevational view oi the beam and probes and showing the structure whereby the probes may be alternately rendered Operable; and

Fig. 10 is a. fragmentary plan view taken substantially along the line Ill-l0 of Fig. 1 and showing, on anenlarged scale. a carriage for supporting the test specimen, parts being broken away to'illustrate a means whereby the test specimen supporting carriage may be shifted transversely oi the path oimovement of the carriage to dispose various portions o! the test specimen to be acted upon by the probes.

In the drawings, the apparatus is illustrated as-'being mounted upon a base member l5, ou`

which there is mounted a brake releasing solenoid Il and a driving motor I1. In addition to supporting the brake releasing solenoid and driving to indicate the amount oi pressure required to A complete understanding of the invention may be had by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein Fig. l is a side elevational view of an apparatus for testing coatings made inaccordance with the present invention;

Fig. 2 is a circuit diagram illustrating the control cireuit schematically;

Fig. 3 is a plan view of the apparatus shown in Fig. l. part being broken away to conserve space;

Fig. 4 is a side elevational view oi the weight supporting carriage which travels along the beam, part oi the beam being broken away to more clearly illustrate details oi the carriage;

Fig. 5 is a transverse vertical sectional view taken substantially along the line l-S of Fig. 4 in the direction oi.' the arrows showing details of construction oi the beam and weight supporting carriage;

Fig. 6 is an irregular vertical sectional view taken substantially along the line H o! Fig. 1

motor. the base I5 supports an inverted channel member I8. the upper surface of which comprises a trackway for a specimen supporting carriage, `designated generally by the numeral Il. Intermediate the ends of the inverted channel member I8, a pair of blocks 20 and 2| are positioned' to serve as spacer members for

bearing plates

22 and 23, respectively, which, together with the blocks 20 and 2|, are attached to the inverted channel member il by means of machine screws 24-24. At the ends oi' the channel member I8,

upright members

25 and 28 are attached thereto to serve as bearings for a pair oi drive screws 21 and 2l journalled in anti-friction bearings in the upright members and adapted to drive the specimen supporting-carriage l! and a weight supporting carriage, indicated generally by the reference numeral 29, respectively.

The drive screws 21 and 28 have gears 20 and 3l ilxed to them and meshing one with another. The gear 3l also meshes with an idler gear 32 suitably mounted for free rotation on the upright member 25 and. in turn, meshing with an intermediate gear 33. The gear I3 is freely rotatable with respect to the upright member 28 and has attached to it a large driving gear 84, which, in turn, meshes with a spur gear 88 on the drive shaft of the motor I1. Thus, when the motor |1 is actuated, rotation will be imparted through the gear train just described to drive the

drive screws

21 and 28 simultaneously. v

Formed integrally with or suitably attached to the gear 3| is a truste-conical brake drum 48 having a brake band 48 attached thereto for cngagement by the internal surfaces of a brake member 41 slidably engaging the reduced end of the screw 28. The brake member 41 is provided with a flange 48 and a head 48 and the iiange 48 is engaged by compression springs 50-50 which surround posts 8I-5I mounted in the upright member 28 and are compressed between the ange 48 and lock nut assemblies 52-52 threaded onto. the posts 5|. Thus, the compression springs 80-88 urge the brake member 41 to engage the brake band 48 on the drum 45. Attached to the head 48 of the brake member 41 is a bracket 53 having a lever 54 pivoted thereto on a pin 85. The lever 54 carries an adjustable abutment member 88, which engages a plate 51 attached to the ends of the posts 8|. The lever 54 is pivotally connected to a solenoid core 58, which, upon actuation of the brake releasing solenoid I8, will be moved to the left,

as viewed in Figs. 1 and 8, to rock the lever 54:

clockwise and withdraw the` brake member 41 from engagement with the brake band 48 whenever the motor I1 is operated, as will be described more in detail hereinafter.

Journalled for free oscillation in anti-friction bearings 85 positioned at the upper ends of the

bearing plates

22 and 28 is a beam supporting yoke 66, to which a channel-shaped beam 81 may be suitably attached, for example, by welding or bolting, the two members together. The channel-shaped beam 81, as shown most clearly in Figs. 6 and 7, has a hat surface 88 milled in it to a suilicient depth to provide a pair of guide shoulders GSi- 88, which serve to guide the wheels 10-10 of the weight-supporting carriage 28. The weight-supporting carriage 28 comprises a weight-supporting plate 1 I, from which there extend four legs 12-12, on each of which there is mounted one of the wheels 10. The legs 12-12 are spaced apart a distance sumcient to receive an irregularly shaped travelling nut 18, which threadedly engages the drive screw 28 and extends transversely of the carriage 28 a suillcient distance to engage the legs 12, whereby, when the drive screw 28 is rotated, the carriage 28 will move along the channel-shaped beam 81. The travelling nut 13 has an upwardly extending portion 14, which enters into the channel of an inverted channel member 15 attached to and extending between the upright members and 28. This channel member serves to prevent rotation of the travelling nut 18 with respect to the carriage 29 and prevents any torque being applied to the carriage 28 which might tend to support the carriage and weights 18-18 mounted on the weight-supporting plate 1|. v

Suitably attached to the under side of the beam 61, as shown most clearly in Figs. 7 and 9,' are a pair of probe-supporting blocks 11 and 11 having

chuck members

18 and 18, respectively, formed integrally with them. The chuck 18 has an aperture 80 formed in it for receiving a probe member 8|, which may be locked in place in the aperture 80 by means of a set screw 82. The probe member 8| is provided with a rounded point 88, which, when engaged with a coating of paint on the test specimen, will abrasively engage the coating and tend to scrape the coating from the test specimen and thereby effect a scratch adhesion test on the specimen. 'Ihe chuck 18 is provided with a probe receiving aperture 88, in which a probe member, designated generally by the numeral 84, may be positioned. The probe member 84 is provided with a shank 88, in which there is formed a groove 88. The shank portion of the probe member 84 extends into the aperture 88 a suiilcient distance so that a flat surface of a knurled ilange 81 will engage a face of the chuck 18 and the groove 88 will be in alignment with the nib of a set screw 88 having a knurled head. Disposed eccentrically with respect to the shank 88 is a needle-receiving portion 88 adapted to receive a needle 80, which is held in the portion 88 by a thumb screw 8|. As shown in the various ilgures of the drawing, the needle is positioned to extend just below the rounded point 88 of the probe 8|. However, upon loosening the set screw 88, the probe member 84 may be rotated to carry its eccentric portion to a higher position than that shown in the various figures and to thus move the needle 88 to a position where its point will be above the rounded point 88 of the probe 8| and then the probe 88 will engage a test panel to make the scratch adhesion test on ay coating on the test specimen or panel. When the probe member 84 is in the position shown in the various figures, a mar resistance test will be made on the test panel. 'I'he probe may be disengaged from the test specimen by manually manipulating an eccentric 84 mounted on a shaft 88, which is journalled in the upright member 28 and is provided with a handle 88, whereby it may be manipulated. yThe eccentric 84 is positioned below the end -of the beam 81 and may be manipulated to raise the beam and carry the probes out of engagement with the specimen on the carriage I8.

In order to counterbalance the weight oi' the probes 8| and 84 and their supporting devices, a weight |82 is attached to the under side of the beam 81 to the left of its bearings (Fig. 1). This weight has a bar |04 attached to it for carrying a threaded support post |08, on which a weight |08 is threaded. The weight |88 is provided with a knurled lock nut |01, whereby the weight may be rotated on the post |88 to adjust the beam 81 and then locked in place so that it will exactly balance when the carriage 28 carrying the weights 18 is in the position shown in Fig. 1, where a reference line |08 on the carriage is at the zero point of a scale |08 scribed on the beam 81. The scale |08 may be graduated to indicate the amount of pressure applied to the probes at the various positions of the carriage 28 along the beam 81.

'Ihe specimen-supporting carriage I8 is adapted to carry a test specimen in the form of a plate or sheet of metal IIII having a protective coating III, which is to be tested. The carriage |8 may be driven by a travelling nut ||2 resting on the upper face of the channel member I8 and threadedly engaging the drive screw' 21. The nut |I2 has a pair of projections |I8I|8 on directly opposite edges thereof for entrance into a series of slots |I4--I I4 formed in oppositely disposed portions ||8 and I I8 of the carriage I8. The portions I|8 and I|8 are made ofinsulating material and each has two legs ||1 extending downwardly from it to rotatably sup- .port wheels I|8| I8, which ride upon the upper surface ci the channel member I3. The portions III and lit are suitably attached to a metallic bed |I3, which is adapted to receive the tt specimen in the iorm of" the sheet of metal Iltwith the coating tobe tested on its upper surface.

Mounted upon the bed I I3 are four pivot blocks |23-'-|24. which carry pivot pins |2| in position to einer an intermediate portion m or s slamp |23 for pivotalw supporting these. clamps in position to clamp Vthe sheet of metal III having the coating III on it in position to be tested. vThe lower tace oi' each oi the clamps |23 has a compressibie insulating material cemented to it. for example, a strip of ielt |24, which will engage the coating II| on the sheet of metal III vto clamp the specimen on the bed III. At their lower ends, the clamps |23 are adapted to receive pivot members |24 and |23, which are freely oscillatable in suitable apertures formed in the lower edge of the clamp |23. The pivotmember I2! engages a reduced portion oi' a rod |21 and is held in place on the reduced portion of the rod |21 by a cap member III pinned to the rod |21. The pivot member |24 is internallythreaded to threadedly engage a threaded portion |23'A o! the rod |21 and rotation may be imparted to the rod |21 by a thumb nut |34 on a reduced square shank I3I ofthe rod |21, which shank is threaded to receive a retainer nut |32. When a test specimen in the 'form oi a metallic plate I|3 with s coating .l l l 'is placed upon meines m, u may be moved into engagementwith an end member |33.'V which is attached to the bed II. whereby, upon movement of the carriage Il, the specimen will not be dragged away from the clamping members |23.,

,The control circuit for controlling the operation 'of the apparatus includes a main power supply switch I44, which, when closed, will connect current from a source I4I to the normally open contacts of a relay |42 and to the normally open contacts of a relay |43. The relay |42, upon energization. serves to supply power to the motor I1 to drive the vmotor in one direction and the relay |43, upon energization, serves to supply currentA to drive the motor I1 in the opposite direction. 'I'he motor I1 has a pair of leads |44, vwhich will maintain it in operation in either direction, and has a pair of leads |44 connected to its. starting winding (not shown) for initiating the operation of the motor I1 in either of two directions, depending upon whether the relay |42 or |43 is operated. Initiation of operation oi' relay |42 may be eii'ected by closing a switch |43 to supply current through a normally closed switch |41 to the winding of relay |42 and, upon energization of relay |42. `the .relayl will lock operated over its locking contacts and the normally closed contact of a relay |43, the normally closed contact oia. reversing switch |43, and the normally closed contacts of an emergency lstop switch |53. Relay |43 operates under control of an amplifier |53 connected to the source of current upon closure of the switch |44 and operable under control oi whichever one of the probe members 2| or 34 is in operative contact with the test specimen on the bed III of the specimensupporting carriage I3. The amplifier Ill is provided to permit the usage of a low value current at the probes. which is ampliiled in the ampliiier to operate relay I 43.

The probe'whlch is being used, upon breaking through the coating on the test specimen. will complete a circuit from the ampliiier |43 through 5 through the coating on the metallic sheet III.

it will complete a circuit through the ampliiler Ill to energize the relay |43 and break the locking circuit to relayy |42. The solenoid II is connected in parallel with the motor I1 and. when m the motor I1 is deenergized. the solenoid |l will also be deenergized. The circuit to the coil ci relay |42, as pointed out hereinbefore. is com-` pleted through normally closed switch |41 andA this switch is mounted upon the channel member is I3 in such position, as indicated in Fig. i. that the specimen-supporting carriage I3 will open the switch |41 when the carriage moves the test specimen to a position where the probes are ad- `iacent the right end of a specimen ,on the ear- 0 riage. The switch |44, in initiating the forward movement of the carriage I3, will complete a circuit 'through the normally closed contacts of switch I and normally closed contacts ofthe emergency stop switch |53 and the circuit 5 through the windings of relay |42 will be maintained by the contacts of relay |44.

,After a specimen has been tested by moving t it beneath`a probe, the carriage I3 may be returned to its right hand position (Fig. l) by o manipulating reversing switch |43, which will break thev locking circuit for relay |42 and momentarilymake a circuit to energize the winding of relay |43 over a circuit from the current source through a normally closed switch |54, the nor- 35 mally open and now closed contacts of switch i |43. stop switch |43 yand back to the current source. As soon as a relay |43 pulls up, it will remain locked up over a circuit from the current source through the stop switch |53, locking contacts of relay |43 and normally closed switch |44, back to the main current source at switch |44. This circuit will be maintained until the carriage I3 reaches its extreme right hand position (Fig. 1) where it will actuate the switch |54 a to open the locking circuit for relay |43 after the'carriage Il is moved from under the probes.

A more complete understanding of the invenftion may be had by reference to the following brief description of the mode of operation of the apparatus. A test specimen. comprising a sheet .of metal I I0 having a coating I I thereon, may be placed upon the bed I It of the carriage I! and the carriage may then be placed on the travelling nut |I2 with the projections I I3 of the nut I I2 nested in opposed notches |I4 in the portions IIB and 55 III of the carriage I9. The carriage may be placed in engagement with the travelling nut I2, as just described, when the nut II2 is in its extreme right hand position and when the beam 61 is heid in its upper inoperative position by the eccentric !4. The specimen supporting carriage |l. thus having been placed in the apparatus with a specimen positioned thereon, switch |40 may be closed to supply current to the various electrically .operated portions of the apparatus and to prepare the apparatus for operation, whereupon switch I 46 may be closedmomentarily to initiate a testing operation, it being assumed that the probe B4 is in either its operative or in its inoperm ative position and is locked therein so that eitherl a mar resistance or scratch adhesion test may be performed and it also being assumed that the proper weights 1t have been placed upon the weight-supporting carriage 23. With the appa- 7;, ratus thus conditioned for operation, the switch A I may be operated to advance the carriage I9 to the position shown in Fig. 1, whereupon the beam 91 may be lowered to engage the probe with the coating III on the sheet of metal III) comprising the test specimen. As the carriage I9 moves to the left from the position shown in Fig. 1 through the action of the travelling nut I I2 and the drive screw 21, the carriage 29 will move to the right due to the cooperation between the drive screw 28 and the travelling nut 13, thus gradually increasing the load applied to the probe bearing on the test specimen. The carriage I9 will continue to move to the left until it engages the switch |41 to release the locking circuit for relay |42 or until the probe breaks through the coating on the test specimen and, through the amplifier |50, energizes relay |48 to stop the operation of the apparatus. If the probe does not break through the coating, the handle 96 may be manipulated to disengage the probes from the test Aspecimen by lifting the right end of the beam 61, and reversing switch |49 may be momentarily operated to interrupt current to relay |42 and supply current to relay |43, to supply a current in a reverse direction through the leads |45 and thus reverse the direction of drive of the motor I1. The motor I1 will continue to drive`the carriage I9 to the right and the carriage 29 to the left until the carriage I9 engages and operates switch |54 to break the locking circuit to the relay |43. 'I'he carriage thus being returned toits right hand or inoperative position, it may be picked up off the travelling nut II2 and reengaged therewith with the projections |I3 engaging the next set of notches I I4 and more weight may be placed upon the carriage 29 and the test specimen may then be retested with more weight on the weight-supporting carriage 29. These testing operations may be repeated, adding more weight to the carriage 29 until the coating III on the sheet of metal IIli has been broken, thereby to measure the mar resistance or scratch adhesion value of the coating III. Furthermore, by changing the position of carriage I9, a series of tests may be made on a single test panel to determine the average mar resistance or scratch adhesion over .different portions of its surface.

It should be noted that each time a circuit is completed to the motor I1, a circuit is completed in parallel to the solenoid I6 to release the brake member 41 from the brake band 4B and that each time the circuit to the motor I1 is broken, solenoid I6 will be deenergized to quickly stop any overrun of the feed screws, whereby the position of the reference line |08 on the weight supporting carriage 29 will give an accurate indication of the amount of weight required to break through the coating with the probe and thereby indicate either the mar resistance or scratch adhesion value of the coating III, depending upon which probe is being used.

What is claimed is:

1. In an apparatus for testing a coating on a test panel, a supporting framework having a flat supporting surface, a rotatable threaded drive shaft longitudinally mounted on said framework in parallel relation to said fiat supporting surface, a nut operatively engaging said threaded drive shaft and slidably engaging said framework for longitudinal movement thereon, a test panel supporting carriage mounted for movement on the supporting surface of said framework, an elongated transversely disposed recess in said carriage having wall portions slidably engageable with portions of said nut, a plurality of vertical slots 8 formed in one of'said wall portions of said carriage, a projection on said nut slidably engageable in said vertical slots, the arrangement of the nut and the carriage being such that the carriage may be vertically applied and connected to said nut in a plurality of lPositions transversely of the movement of the"n`ut for longitudinal movement therewith, means on said carriage for clamping said panel thereto, a test probe engageable with the coating of a panel on said carriage, and means operable in timed relation to the rotation of said drive shaft for increasing the pressure of said probe on said coating.

2. In an apparatus for testing a coating on a test panel, a supporting framework having a supporting surface, a rotatable threaded drive shaft longitudinally mounted on said framework in parallel relation to said surface, a nut operatively engaging said threaded drive shaft and slidably engaging said framework for longitudinal movement thereon, a test panel supporting carriage supported for movement on the supporting surface of said framework, an elongated transversely disposed recess in said carriage having wall portions slidably engageable with portions of said nut, a plurality of vertical slots formed in one of said wall portions of said carriage, 9, projection on said nut slidably engageable in said vertical slots, the arrangement of the nut and the carriage being such that the carriage may be vertically applied and connected to said nut in a plurality of positions transversely of the movement of the nut for longitudinal movement therewith, a test probe engageable with the coating of a panel on said carriage, a, beam pivoted on said framework and extending longitudinally thereof for supporting said test probe, a weight supportingcarriage movable along said beam, a second rotatable threaded drive shaft longitudinally mounted on said framework in spaced relation to said beam, a nut operatively engaging said second drive shaft for longitudinal movement thereon, a channel member mounted on said framework adjacent and in parallel relation to said second drive shaft and engageable with the nut thereon to prevent its rotation. said weight supporting carriage having portions vertically slidably engageable with the nut on said second drive shaft for connecting said carriage to saidnut for longitudinal movement therewith, and means for simultaneously driving said drive shafts.

3. In an apparatus for testing a coating on a A test panel, a supporting framework having a supporting surface thereon, a rotatable threaded drive shaft longitudinally mounted on said framework parallel to said supporting surface. a nut operatively engaging said drive shaft and slidably engaging said framework for longitudinal movement thereon, a test panel supporting carriage supported for movement on the supporting surface of said framework, said carriage being recessed to receive a portion of said nut therein to establish a driving connection with said nut for longitudinal movement therewith, a test probe for engaging the coating of a panel on said carriage, a beam pivoted on said framework and extendmg longitudinally thereof for supporting said test probe, a weight-supporting carriage movable along said beam, a second rotatable threaded drive shaft longitudinally mountedin said framework in spaced relation to said beam, a nut operatively engaging said second drive shaft for longitudinal movement thereon, a channel member mounted on said framework in parallel relation to said second drive shaft and engageable with the nut thereon to prevent its rotation, said weight supporting carriage having portions vertically slidably engageable with said nut for connecting said carriage to said nut for longitudinal movement therewith, and a power drive for simultaneously driving said drive shafts.

4. In an apparatus for testing a coating on a test panel, a supporting framework having a supporting surface and a pair of upwardly extending end walls, a pair of rotatable threaded drive shafts journalled one above the other in said walls in spaced and parallel relation to the supporting surface of said framework and with the lowermost shaft adjacent thereto, a nut operatively engaging said lowermost drive shaft for longitudinal movement thereon and slidingly engaging the supporting surface of said framework, a nut operatively engaging the upper drive shaft for longitudinal movement thereon, a channel member mounted on said walls in spaced and parallel relation to said upper drive shaft and engageable with said nut for preventing the rotation thereof, a beam pivotally mounted on said framework and extending longitudinally thereof adjacent said upper drive shaft, a test panel carriage supported for movement on said flat supporting surface of said framework and engageable with the nut on said lower drive shaft for longitudinal, movement therewith, a test probe mounted on said beam and engageable with the coating of a panel on said panel carriage, a weight supporting carriage movable longitudinally on said beam and vertically slidably engageable with the nut to establish a, connection therewith for longitudinal movement with said nut, drive means for simultaneously rotating said drive shafts, and a cam member mounted on said wall and engageable with the end of said beam for moving the end thereof to raise the probe from the panel.

5. In an apparatus for testing a coating on a test panel, a supporting framework having a straight supporting surface and a pair of upright frame elements, a pair of rotatable threaded drive shafts journalled one above the other in said frame elements in spaced and parallel relation to the supporting surface of said framework and with the lowermost shaft adJacent thereto, a

10 nut operatively engaging said lowermost drive shaft for longitudinal movement thereon and slidably engaging the supporting surface of said framework,` a nut operatively engaging the upper drive shaft for longitudinal movement thereon, a member mounted on said frame elements in spaced and parallel relation to said upper drive shaft and engageable with said nut for preventing the rotation thereof, a beam pivotally mounted on said framework and extending longitudinally thereof adjacent said upper drive shaft, a test panel carriage mounted for movement on the supporting surface of said framework and engageable with the nut on the lower drive shaft for longitudinal movement therewith, means including cooperating portions on said test carriage and the nut on said lower drive shaft for laterally adjustably connecting said test carriage to said nut for longitudinal movement therewith, a test probe mounted on said beam and engageable with the coating on a panel on said panel carriage, a weight supporting carriage movable longitudinally on said beam and vertically slldably engageable with the nut on the upper drive shaft to establish a connection therewith fo'r longitudinal movement with said nut, drive means for simultaneously rotating said shafts, and means mounted on one of said frame elements operable to tilt said beam to raise the probe from the panel.

JEROME R. MARCUS.

REFERENCES CITED The following references areof record in the le of this patent:

Germany Sept. 9, 1929